/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicMesh3.h
Insert vertex at given index, assuming it is unused. If bUnsafe, we use fast id allocation that does not update free list. You should only be using this betweenBeginUnsafeVerticesInsert()/EndUnsafeVerticesInsert()calls
[EMeshResult](API\Runtime\GeometryCore\UE__Geometry__EMeshResult) InsertVertex ( int VertexID, const [FVertexInfo](API\Runtime\GeometryCore\DynamicMesh\FVertexInfo) & VertInfo, bool bUnsafe )